An estimated 8.3 billion metric tons of virgin plastics have been produced, a sum that seems both impressive and almost unimaginable when you take into account that plastics have only been produced for a little more than 70 years.
Plastics did not enter mass production until the late 1940s beginning with new products such as Tupperware, which launched in 1948. In 1951, scientists working for Phillips Petroleum developed High-Density Polyethylene (HDPE), and in 1967 the dairy industry began using the product for the packaging of milk. But, it was not until 1973 when Nathaniel Wyeth, while working for DuPont, patented the soda bottle made of Polyethylene Terephthalate (PET). Because of its strength to hold two atmospheres of pressure, the bottling industry embraced it and the production and sale of plastic products boomed.
However, the very thing that has made plastic what it is today—its durability—is also posing a huge environmental problem. Plastics are synthetic and do not decompose like bio-based products. To answer this problem, in the 1980s, major U.S. cities began establishing plastic recycling programs, and by 1984, plastics recycling topped 100 million pounds.
To cope with the amount of plastics and other recyclable materials, waste removal companies have built large recycling facilities to sort, separate, and package all of the waste. Companies like General Kinematics (GK) developed Multi-Stream™ Recycling Equipment to assist in the recycle sorting process. When combined with robotic arms powered by artificial intelligence, GK’s equipment can process waste faster and more accurately, while saving money and the environment.
But, despite the introduction of single-stream recycling on the consumer end, automated sorting at the collection center, and new processes to make used plastic products into new products, the problem is getting worse.
Reports show that in 2015, approximately 6,300 metric tons of plastic waste was generated, of which around 9 percent had been recycled, 12 percent was incinerated, and 79 percent was accumulated in landfills or discarded in the natural environment.
Contributing to the problem is the fact that not all plastics are recyclable or reusable.
Plastics by the numbers
The well-recognized “chasing arrows” symbol we see on plastic containers and products does not mean the product is recyclable. The little number inside the triangle tells the real story.
Understanding the seven plastic codes will make it easier to choose plastics and to know which plastics to recycle. In general, numbers 3, 6, and 7 are not recyclable plastics. While numbers 4 and 5 are recyclable, many municipalities have not started recycling that plastic and simply send it on to the landfill.
#1 – PETE (Polyethylene Terephthalate) is one of the most commonly used plastics in consumer products, and is found in most water and soda bottles,
#2 – HDPE (High-Density Polyethylene) is the stiff plastic used to make milk jugs, detergent and oil bottles, toys, and some plastic bags. HDPE is the most commonly recycled plastic and is considered one of the safest forms of plastic.
#3 – PVC (Polyvinyl Chloride) is dubbed the “poison plastic” because it contains numerous toxins which can leach throughout its entire lifecycle. Almost all products using PVC — such as clear plastic food wrapping — require virgin material for their construction, making this form of plastic not recyclable.
#4 – LDPE (Low-Density Polyethylene) is often found in shrink wraps, dry cleaner garment bags, squeezable bottles, and grocery bags. LDPE is considered less toxic than other plastics, and relatively safe for use. It is not commonly recycled, although this is changing as more recycling programs gear up to handle this material.
#5 – PP (Polypropylene) plastic is tough and lightweight, and has excellent heat-resistance qualities often used as the thin plastic liner in a cereal box. Polypropylene is considered safe for reuse and is recyclable through some curbside recycling programs.
#6 – PS (Polystyrene) is an inexpensive, lightweight and easily-formed plastic most often used to make disposable Styrofoam drinking cups, take-out “clamshell” food containers, egg cartons, and those ubiquitous “peanut” foam chips used in shipping boxes. Because polystyrene is structurally weak and ultra-lightweight, it breaks up easily and is dispersed readily throughout the natural environment. Polystyrene may leach styrene, a possible human carcinogen, into food products (especially when heated in a microwave). Chemicals present in polystyrene have been linked to human health and reproductive system dysfunction. Recycling is not widely available for polystyrene products.
#7 – Other (BPA, Polycarbonate, and LEXAN) The #7 category was designed as a catch-all for polycarbonate (PC) and “other” plastics, so reuse, and recycling protocols are not standardized within this category. Of primary concern with #7 plastics is the potential for chemical leaching into food or drink products packaged in polycarbonate containers made using BPA (Bisphenol A). BPA is a xenoestrogen, a known endocrine disruptor.
Plastics are Changing
As pointed out earlier, the plastic types in the above categories are resistant to biological elements and, instead of decomposing, they simply sit in landfills or litter the environment for thousands of years. Entire islands of plastic have been found floating in the oceans of the world.
But a new plastic, Polylactic acid (PLA) has been developed and is designed to decompose over a period of months or in just a few years. PLA is derived from corn starch—a polysaccharide—or a long chain of sugar molecules fused together.
PLA is being used to make eco-friendly plastic drinking cups, plates, and eating utensils. PLA is also being used to manufacture plastic bags and fibers for clothing.
The cellulose from the corn stalks also naturally decomposes and can be turned into cellophane for wrapping food, or rayon fibers for material.
Changing Habits is Key
Many companies are taking steps to reduce the amount of plastic waste by reducing the amount of plastic packaging. Fast food companies are moving away from polystyrene clamshells and drink cups and using paper instead of plastic. Some cities and states have banned the use of plastic grocery bags, urging customers to bring reusable bags to the store.
To promote recycling in general, many companies are placing recycle bins in convenient locations throughout their buildings and posting recycling totals on bulletin boards to encourage goal setting.
One of the biggest advances in the development of recycling has been the use of single-stream recycling. With this process, residents of the community no longer need to worry about sorting their waste but instead combine their paper, cardboard, glass, metal, and plastic into a single recycling container, which is then sorted at the recycling center. The simplicity of single-stream recycling has been shown to increase recycling rates by an average of 30 percent.
For many large recycling centers, General Kinematics technology does much of the work. And new technology is just around the corner.
While recyclers are struggling with current recycling technologies, inventors are working on a process that will combine the entire spectrum of plastic products into dense molded building products that are resistant to moisture, heat, and, of course, will not rot or decompose. When perfected, this process will remove nearly 100 percent of the plastic waste from landfills and, with the amount of available plastic waste, reduce the need for lumber in the building industry.
Meanwhile, the General Kinematics R & D Laboratory is working full time to improve and advance the technology of vibratory and other automated screening recycling equipment that improve efficiency and reduce labor costs, making recycling more effective as well as an economically viable solution.
